I'm tearing down what I hope to be a rebuildable core. When I removed the rear most freeze plug, it had a solid wall of rust behind it! How much rust is normal inside the water jacket? I dug out a full coffee cup of rust with a screwdriver just from that one plug.

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If it was easy, everybody would be doing it.

All of it. There are various techniques for cleaning the water jackets. See here.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks, Dan. I was just shocked at how much rust was in there. I don't know the history of this engine other than it ran in propane, but I would imagine it always ran hot. There is no passage at all around that side of the cylinder.

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If it was easy, everybody would be doing it.

Well, Propane is a cooler-burning fuel, without the energy available in the equivalent volume of gas. That shouldn't have that much effect on what you describe. If it's a propane engine, that suggests prior forklift duty, thus quite possibly neglect of the cooling system.

A good cleanup and boil-out should fix the problem, then a few flushes during your first couple thousand miles.

Roger

I went ahead and removed all of them. They weren't quite as bad as that one but I think I should have this engine checked for cracks and get the deck shaved a little bit. I don't know the original application but it appears it was worked pretty hard. The oil had lots of copper flakes in it.

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If it was easy, everybody would be doing it.

After partial disassembly, I am certain this engine lived an industrial life. They used straight water for coolant, which would mean it probably never went outside. I'm thinking warehouse forklift. It's painted battleship gray, has a truck oil pan, no vacuum advance on the distributor, and had a propane carburetor. Definitely going to be a fun rebuild. Hydraulic lifters too. Date code is late 1983.

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If it was easy, everybody would be doing it.

Read that whole thread that Dan gave you, stay away from HF, hydrofluoric acid, there is good advice in that thread on HF.

Muriatic acid is an impure form of HCl, hydrochoric acid, and as they point out in the thread, works great to dissolve rust from the block. Neutralize with a base such as sodium bicarb solution. Be careful - muriatic acid will etch cylinder walls, and mating surfaces of head and block if they are exposed to it.

NOTE: I've used, and promoted the use of, a rust remover called EvapoRust. See thread here: http://slantsix.org/forum/viewtopic.php ... light=edta I highly recommend anyone who hasn't tried this stuff to give it a whirl, amazing stuff. No dangerous fumes, water based, only slightly basic pH.

This would work great in an engine block, in fact the Navy uses it for derusting engines. The solution is slightly basic and will not touch the metal, only the rust and it is reusable (up to a point). Thus if you e.g. use DD's long block circulation method, there is no worry if it gets into the cylinders and such, it will not remove the base metal, it is highly selective for iron oxide.

Brian

P.S. I am not affiliated in any way with EvapoRust's maker or any material supplier thereto. I just love this stuff, it's chemistry that really works...

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https://tinyurl.com/yynpj4v2

Perfect timing! I was just reading about evaporust online and a guy was using it on an old transmission. Looks like it would do exactly what I need.

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If it was easy, everybody would be doing it.

Even cheaper than EvapoRust: Molasses! See here and here.

(And yes, hydrofluoric acid is best left far, far, far alone.)

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Molasses, eh? I might do that for some rusty suspension pieces I have in the garage...

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If it was easy, everybody would be doing it.

I didn't know molasses were chock full of chelators...

Evaporust is $17/gallon and you can dilute it up. If you want speed, use a couple gallons to remove rust much faster. I used it full strength and it worked pretty fast, like a few hours and you could see most of the rust was gone, overnight did the rest. Diluted up it took a few days or so when I did the K frame.

The only thing I'd worry about with Molasses is ants! That said, I can't wait to try it.

Brian

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https://tinyurl.com/yynpj4v2

On closer inspection it looks like he had mold growing in his tank of molasses. i would expect that, might be stinky. Evaporust doesn't smell bad and doesn't mold.

b

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https://tinyurl.com/yynpj4v2

Do you guys have companies over there that "dip" car bodies to strip them of paint and rust? I personally don't like this process for bodies due to chemicals staying between panel seams,but I do get my blocks dipped there and they come up a treat. For the $100 or so bucks they charge it's worth my time to keep my shop clean and know it's done in some kind of enviromentally responsible way...kind of...but mainly so I don't have the mess at my place. That being said I have used a chemical rust remover available over here at hardware store on small parts and it works great,it certainly would clean a water jacket quite well.

Remember all that rust is from your cast block,sure the slants are pretty thick in the bores,but core shift is a possibility,throw in some heavy corrosion pitting and I'd be cautious about porosity in the bores. When you get it bored keep an eye on the fresh finished bores,if any dark spots appear over time it may be a thin spot . Another option is get the block dry,spray a penetrating oil in the water jackets around the bores and dust the inside of the bores with talc to see if any wet spots leech through,or pressure test it

I think I will use the molasses for the suspension pieces I have tucked away because I have a big enough bucket for that, one with a lid because of the potential stink factor. Evaporust for the engine block. I plan on getting this block checked for cracks and whatnot before I go too far into it.

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If it was easy, everybody would be doing it.

Molasses works but as any such solution you have to work quick after the
rinse to stop flash rusting. Evaporust flat out rocks! And protects the metal
against rusting when you're done. I did a set of GLH coils by wire wheeling
them 1st, then putting them in a 3gal. bucket of ER, using water filled jug/
bottles to displace the volume so I didn't need 3 gal of product. Perfect
results.